Apparatus for making elastic bands



Nov. 11, 1958 w. H. SPENCER APPARATUS FOR MAKING ELASTIC BANDS Original FiledJuly 1a. 1952 3 Sheets-Sheet 1 ATTQQNEY Nov. 11,1958 w. HQ SPENCER APPARATUS FOR MAKING ELASTIC BANDS Original Filed July 18, 1952 3 Sheets-Sheet 2 n L- IIIIIHIMLIHHHIIIIIIII-HIINV'IHHHHHHIHHHT 1 1 HH I I l HU "HHIIHIII. 'T 3 I IIIII l l nl ll l l l l hhh ul lflp uw l H H H I I l "n" H l u l I .I H 3 r 8 2 H U N m ATTORNEY Nov. 11, 1958 w SPENCER 2,859,474

APPARATUS FOR MAKING ELASTIC BANDS Original Filed July 18, 1952 3 Sheets-Sheet 3 as as 35 3 l2 FIG. 5

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wad/M ATTORNEY United States atent APPARATUS FOR MAKING ELASTIC BANDS William H. Spencer, Alliance, Ohio Original application July 18, 1952, Serial No. 299,549, now Patent No. 2,781,550, dated February 19, 1957. Divided and this application August 21, 1956, Serial No. 605,919

7 Claims. (Cl. 18-6) This invention relates to a method and apparatus for a vulcanizer at about 190 F. for a vulcanizing cycle,

removing the mandrel from the vulcanizer, removing the rubber tube from the mandrel, and cutting the tube into narrow bands of vulcanized rubber. This method, generally, has a serious disadvantage that it has been difiicult to expand or mount the unvulcanize-d tubing onto the mandrel, and to remove the vulcanized tubing from the mandrel. Tubing mounted on a mandrel of relatively smaller diameter than the tubing has been objectionable because sagging of the tubing caused the elastic bands to be elongated or ovate instead of circular; moisture condensation on the inner surface of the tubing, from the vulcanizing steam ostensibly had a tendency to weaken the elastic bands; and over-curing at the points of contact of the tubing with the mandrel, usually metal, had a similar tendency to weaken the elastic bands at said points of contact.

One object of the present invention is to provide a method and apparatus by which the unvulcanized, extruded tubing of rubber-like material is easily mounted on a mandrel of relatively smaller diameter, and wherein the tube is maintained truly circular during the vulcanization process.

Another object of the invention is to provide a method and apparatus of the character described wherein localized metal to rubber contact and condensation ofmoisture are obviated, whereby the elastic bands produced will be of substantially uniform elasticity and strength throughout.

Other objects of the invention will be manifest from the following brief description and the accompanying drawings: V

Of the accompanying drawings:

Figure l is a side elevation, partly in cross-section, illustrating'an open steam type vulcanizerutilized in connection with the invention.

Figure 2 is a diagrammatic illustration of a portion of the apparatus used in practicing the method of the invention.

Figure 3 is a perspective view of a full-circle rubber band made by said method.

Figure 4 is an enlarged vertical cross-section taken longitudinally through the vulcanizer of Figure 1, and illustrating the improved vulcanizing apparatus.

Figure 5 is a cross-section, on the same scale, taken substantially on the line 55 of Figure 4.

Referring to Figures 1, 4 and 5, there is illustrated an open steam type vulcanizer having a door 11 at one end of the same for passage of a mobile tube vulcanizing unit or support 12, said unit including a truck 13 provided with wheels 14 adapted to run on fixed track means 15 within the vulcanizer and retractible track means 16 exteriorly thereof. On the truck 13 is a tubesupporting reel 17 having a central shaft 18 journalled in bearings 19 and 20 at the upper ends of spaced uprights 21 and 22 on the truck, whereby the reel is rotatable about a horizontal axis. Shaft 18 has a rounded end portion 182 engageable with a stop block 23 on the inner face of door 11, when a clutch part 24 fixed on the other end of the shaft is in clutching engagement with a complemental clutch part 25 on the axially aligned end of a driven shaft 26 journalled in a bearing 27 in the corresponding end wall of the vulcanizer. Driven shaft 26 is rotated at desired-speed by suitable power mechanism indicated generally at 28 in Figure 1.

The reel 17 is designed to support a plurality of cylindrical mandrels 30 in a manner to provide desired rotative movement to rubber tubing material received thereon as the reel is rotated. Accordingly, said reel may include axially spaced outer and inner disc-like end plates 31 and 32, respectively, each having therethrough a plurality of radially and circumferentially relatively closely spaced circular openings 33, 33 and 34, 34, of substantially larger diameter than the cross-section of the mandrels (see Figures 4 and 5), the lowermost edge portions of the respective aligned openings 33 and 34 being adapted to support protruding ends of the mandrels 30 having tubing 35 supported thereon in a manner to be described. The mandrels 30 may be retained against axial movement on the reel at the inner end thereof by a disc-like plate 36 fixed on the shaft 18 in inwardly spaced re.ation to end plate 32 and by a plate 37 mounted on the shaft 18 to be axially shiftable outwardly from and inwardly toward spaced relation thereof to the outer end plate 31. Plate 37 may be locked in this spaced relation, shown in Figure 4, as by means of a bayonet joint connection 38 between plate 37 and disc 31, the same being locked and unlocked by rotation of said plate by means of hand grips 39, 39 on the same. The arrangement is such that when the shiftable plate is moved outwardly of plate 31 (see chain-dotted lines at the right of Figure 4) the mandrels are axially movable endwise to the right to release the opposite ends thereof from engagement through the openings 34 of inner plate 32, whereby the mandrels are readily removable from the reel. Insertion or loading of the mandrels in the reel is accomplished in converse manner, the loading and unloading operations, of course, being accomplished while the unit 12.

is outside the vulcanizer.

In operation of the apparatus described for practicing the improved method herein the unit 12, while located outside vthe vulcanizer 10 with the retaining plate 37 in the released position shown in chain-dotted lines in Figure 4, may have a series of mandrels 30 mounted in horizontal supporting position between the aligned openings 33 and 34 of end plates 31 and 32, respectively, these mandrels having supported thereon lengths of vulcanizable rubber or like tubing 35 from an extruding machine (not shown). As previously described the mandrels may be thus positioned on the reel by inserting the right hand ends of the same (see Figure 4) endwise through the openings 33 of outer plates 31 and then moving mandrels endwise to the left to insert the corresponding ends thereof through the openings 34 of the inner end plate 32, after which the retaining plate 37 is moved axially inwardly on shaft 18 and turned in proper direction to lock it in retaining position, through operation of the bayonet connections 38.

When the loaded mandrels 30 are all in position, the unit 12 is moved into the vulcanizer 10 until the clutch parts 24 and 25 are properly engaged, and the door 11 of the vulcanizer is closed, after which mechanism -28 is operated to rotate the reel 17, through driven shaft 26. The tubes 35 on the rotary reel are: exposed to the usual vulcanizing heat of open steam, contained in the vulcanizer at about 190 F. for about 12 minutes, after which the mechanism 28 is stopped and the unit 12' is removed from vulcanizer for removal of the mandrels 30 from the reel 17 as previously described.

The method of the invention will be best understood by reference to Figure 2, wherein a fixed point a is indicated on the inner periphery of the large opening 33 (or 34) of plate 31 (or 32). When the reel makes a full revolution the point a" will also make a full revolution, as indicated by chain'dotted positions of the opening 33. With each said revolution of point a the mandrel 3% will make a number of revolutions in clockwise direction, whereby the tube 35 supported on the mandrel is fricticnally driven by the mandrel to rotate in clockwise direction. in the proportions shown in Figure 2 the rubber tube 35 would make at least one revolution with each revolution of the reel 17, so that if the reel makes twelve revolutions during a vulcanizing cycle, for example, the tube may also revolve about twelve times during the same period. The amount or speed of rotation of the tube 35 during the vulcanizing cycle may be varied to suit various conditions, such as the diameter of the tubing or the thickness thereof, or the grade of rubber. The diameter of the mandrel may also be varied to suit conditions, but in any event the diameter of the mandrel should be smaller than that of the tubing 35 so that the latter will be freely suspended from a contacting area along the upper portion of the mandrel, as shown.

Rotation'of the tube 35 during vulcanization thereof prevents scorching of the rubber along the area of contact of the tube with the hot metal of mandrel 30. Moreover, such rotation prevents accumulation of condensate at the bottom of the tube which would adversely aifect uniform vulcanization of the rubber. The particles of the rubber are uniformly aligned and the total result is a tube of uniformly circular cross-section. Narrow elastic bands E, cut from this tube, in known manner, similarly will be of uniformly circular cross-section and of substantially uniform elasticity and tensile strength. A finished elastic band B is shown in Figure 3.

Generally speaking the method herein contemplates rotation of an elongated'tube of vulcanizable elastic material while supporting the same by a portion of its peripheral wall along its entire length, and at the same time exposing the tube to openheat of vulcanization. Satisfactory speeds for this purpose have been found to be between one half and five revolutions per minute. In the reel 17 shown in the drawings the aligned openings 33 and 34 thereof may be, for example, approximately 2% inches, while the mandrels used therewith may be within a range 1% to 2 inches in diameter, depending upon the size of elastic bands to be made from the tubing. Rotation of the reel, and hence the mandrels, may be in alternately reversed directions to obviate any tendency toward twisting of the tubing.

Modifications of the invention may be resorted to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. Apparatus for making circular elastic tubing as for making elastic bands, comprising a reel mounted to be rotatable about a horizontal axis and having axially spaced end walls provided with axially aligned circular openings, mandrels of circular cross-section smaller than said circular openings and adapted to be smaller than the internal diameter of the tubing, whereby the latter will be substantially freely suspended from the mandrels to have relatively narrow areas of contact therewith, said mandrels being adapted to be supported between the lowermost portions of aligned said circular openings with said tubing thereon, means for rotating said reel with R sultant rotation of the mandrels about the axes thereof,

and means for vulcanizing said tubing on the mandrels while said reel is rotated, whereby said areas of contact of the tubing with the mandrels will be progressively changed by relative rotation thereof on the mandrels and the tubing will be substantially uniformly vulcanized while the circular shape thereof is maintained.

2. Apparatus for making circular elastic tubing as for making elastic bands, comprising a reel mounted to be rotatable about a horizontal axis and having axially spaced end walls provided with axially aligned circular openings, mandrels of circular cross-section smaller than said circular openings and adapted to be smaller than the internal diameter of the tubing, whereby the latter will be substantially freely suspended from the mandrels to have relatively narrow areas of contact therewith, said mandrels being adapted to be supported between the lov ermost portions of aligned said circular openings with said tubing thereon, means for vulcanizing said tubing while said reel is rotated for consequent rotation of the mandrels about the axes thereof, whereby said areas of contact of the tubing with the mandrels will be progressively changed by relative rotation thereof on the mandrels and the tubing will be substantially uniformly vulcanized while the circular shape thereof is maintained, said reel being mounted on a mobile support and having thereon a central shaft extension, said means for vulcanizing including a vulcanizing chamber, a driven shaft within said chamber, means for aligning said shaft extension with said driven shaft, and releasable connecting means on said shaft extension and driven shaft whereby said reel is rotated by the driven shaft.

3. Apparatus for making circular elastic tubing as for making elastic bands, comprising a reel mounted to be rotatable about a horizontal axis and having axially spaced end walls provided with axially aligned circular openings, mandrels of circular cross-section smaller than said circular openings and adapted to be smaller than the internal diameter of the tubing, whereby the latter will be substantially freely suspended from the mandrels to have relatively narrow areas of contact therewith, said mandrels being adapted to be supported between the lowermost portions of aligned said circular openings with said tubing thereon, means for rotating said reel with resultant rotation of the mandrels about the axes thereof, and means for vulcanizing said tubing on the mandrels while said reel is rotated, whereby said areas of contact of the tubing with the mandrels will be progressively changed by relative rotation thereof on the mandrels and the tubing will be substantially uniformly vulcanized while the circular shape thereof is maintained, said reel having stop means axially outwardly of at least one of said end walls for retaining engagement by corresponding ends of said mandrels extended through said circular end wall openings.

4. Apparatus for making circular elastic tubing as for" making elastic bands, comprising a reel mounted to be rotatable about a horizontal axis and having axially spaced end walls provided with axially aligned circular openings, said openings of the end walls being in radially and peripherally spaced relation, mandrels of circular cross-section smaller than said circular openings and adapted to be smaller than the internal diameter of the tubing, whereby the latter will be substantially freely suspended from the mandrels to have relatively narrow areas of contact therewith, said mandrels being adapted to be supported between the lowermost portions of aligned said circular openings with said tubing thereon, means for rotating said reel with resultant rotation of the mandrels about the axes thereof, and means for vulcanizing said tubing on the mandrels while said reel is rotated, whereby said areas of contact of the tubing with the mandrels will be progressively changed by relative rotation thereof on the mandrels and the tubing will be substantially uniformly vulcanized while the circular shape thereof is maintained, said reel having stop means axially outwardly of at least one of said end walls for retaining engagement by corresponding ends of said mandrels extended through said circular end wall openings.

5. Apparatus for making circular elastic tubing as for making elastic bands, comprising a reel mounted to be rotatable about a horizontal axis and having axially spaced end walls provided with axially aligned circular openings, said openings of the end walls being in radially and peripherally spaced relation, mandrels of circular cross-section smaller than said circular openings and adapted to be smaller than the internal diameter of the tubing, whereby the latter will be substantially freely suspended from the mandrels to have relatively narrow areas of contact therewith, said mandrels being adapted to be supported between the lowermost portions of aligned said circular openings with said tubing thereon, means for vulcanizing said tubing while said reel is rotated for consequent rotation of the mandrels about the axes thereof, whereby said areas of contact of the tubing with the mandrels will be progressively changed by relative rotation thereof on the mandrels and the tubing will be substantially uniformly vulcanized while the circular shape thereof is maintained, said reel being mounted on a mobile support and having thereon a central shaft extension, said means for vulcanizing including a vulcanizing chamber, a driven shaft within said chamber, means for aligning said shaft extension with said driven shaft, and releasable connecting means on said shaft extension and driven shaft whereby said reel is rotated by the driven shaft, said reel having retaining means axially outwardly of at least one of said end walls for retaining engagement by ends of said mandrels extended through said circular end wall openings.

6. Apparatus for making circular elastic tubing as for making elastic bands, comprising a support, an elongated mandrel, means for removably and rotatably mounting said mandrel on said support to rotate about an axis of the mandrel, means for rotating said mandrel on said support, said mandrel being of relatively small diameter compared with the internal diameter of the tubing whereby tubing received on the mandrel is adapted to be substantially freely suspended from the mandrel along a relatively narrow area of contact therewith, and whereby as the mandrel is rotated, said tubing is rotated thereon progressively to change said area of contact of the tubing with the mandrel in direction peripherally around the same, and means for heat curing the tubing while the mandrel is rotated to set the tubing in circular form.

7. Apparatus for heat-curing circular elastic tubing as for making elastic bands, comprising a movable support having spaced members each provided with a plurality of axially aligned circular openings, a plurality of mandrels each having opposite end portions of smaller diameter than said aligned circular openings, said opposite ends of the mandrels being in supporting reception in the lowermost portions of said openings, said mandrels each having an elongated intermediate portion adapted to be of smaller diameter than elongated elastic tubing, whereby the latter will be substantially freely suspended from the mandrels to have relatively narrow areas of contact therewith, means for moving said support gravitationally to revolve said mandrels in said aligned circular openings and thereby progressively to revolve tubing on the mandrels, and means for heat-curing said tubing while being so revolved, said progressive movement of the tubing being adapted to maintain circular shape of the same during heat curing thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,557,439 Kmentt June 19, 1951 2,543,315 Fabregat Feb. 27, 1951 

